U.S. patent number 4,644,014 [Application Number 06/604,645] was granted by the patent office on 1987-02-17 for foamed insulation and process for producing the same.
Invention is credited to R. Keene Christopher, Donald W. Thomson.
United States Patent |
4,644,014 |
Thomson , et al. |
February 17, 1987 |
Foamed insulation and process for producing the same
Abstract
An insulating foam and a process for producing insulating foam,
wherein a foamable first component may be made of alkyl sulfate,
half ester of maleic anhydride and acrylic resin in an aqueous
solution is mechanically foamed with air, and to that foam is added
an aqueous solution of magnesium oxide, dispersant, acrylic resin,
perlite and/or precipitated calcium carbonate. To those components
is added an aqueous solution of at least one of aluminum chloride,
magnesium sulfate, magnesium chloride, zinc chloride, sulfamic
acid, sodium silicate, zinc oxide, barium metaborate, vinyl
alcohol, magnesium carbonate, calcium chloride and vinyl acetate.
In another embodiment a polyvinyl alcohol and dispersant first
portion is foamed with air and mixed with a second cementitious
portion comprising magnesium oxide and barium metaborate. Such two
or three portion compositions can be mixed in the mixing chamber of
a foaming gun which immediately after foam-mixing injects the
foamed mixture into a desired site, such as a building wall.
Inventors: |
Thomson; Donald W. (Inverness,
FL), Christopher; R. Keene (Weedsport, NY) |
Family
ID: |
23643728 |
Appl.
No.: |
06/604,645 |
Filed: |
April 26, 1984 |
PCT
Filed: |
August 29, 1983 |
PCT No.: |
PCT/US83/01335 |
371
Date: |
April 26, 1984 |
102(e)
Date: |
April 26, 1984 |
PCT
Pub. No.: |
WO84/00921 |
PCT
Pub. Date: |
March 15, 1984 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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414953 |
Sep 3, 1982 |
|
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Current U.S.
Class: |
521/68;
52/309.11; 264/DIG.7; 264/46.4; 264/123; 425/817R; 521/136;
521/141; 523/219; 52/742.13; 118/24; 118/303; 264/31; 264/46.5;
422/133; 521/54; 521/55; 521/139; 523/218 |
Current CPC
Class: |
B29B
7/7438 (20130101); C04B 28/32 (20130101); C04B
28/30 (20130101); E04F 21/085 (20130101); C04B
38/106 (20130101); B01F 3/04446 (20130101); E04B
1/7604 (20130101); B01F 5/0695 (20130101); C04B
38/106 (20130101); C04B 12/04 (20130101); C04B
14/18 (20130101); C04B 14/26 (20130101); C04B
14/28 (20130101); C04B 14/30 (20130101); C04B
14/304 (20130101); C04B 18/082 (20130101); C04B
22/0013 (20130101); C04B 22/124 (20130101); C04B
22/141 (20130101); C04B 22/142 (20130101); C04B
24/02 (20130101); C04B 24/06 (20130101); C04B
24/16 (20130101); C04B 24/2623 (20130101); C04B
24/2641 (20130101); C04B 24/2664 (20130101); C04B
40/0028 (20130101); C04B 2103/408 (20130101); Y10S
264/07 (20130101); Y02W 30/92 (20150501); Y02W
30/91 (20150501); C04B 2111/28 (20130101) |
Current International
Class: |
C04B
28/00 (20060101); C04B 28/30 (20060101); C04B
28/26 (20060101); C04B 28/10 (20060101); E04F
21/08 (20060101); E04B 1/76 (20060101); E04F
21/02 (20060101); C08J 009/30 (); C08J 009/32 ();
B29C 039/10 (); E04B 002/34 () |
Field of
Search: |
;264/46.5,31,121,DIG.6,DIG.7,50,45.3,46.4,123 ;52/309.11,743
;118/24,303 ;422/133 ;425/817R ;521/68,54,55,136,139,141
;523/218,219 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Anderson; Philip
Attorney, Agent or Firm: Parkhurst & Oliff
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of our prior pending
application Ser. No. 414,953, filed Sept. 3, 1982, now abandoned.
Claims
What is claimed is:
1. A process for producing insulating foam, comprising:
(a) mechanically foaming with air a foamable first component
comprising an alkyl sulfate and a half ester of maleic
anhydride;
(b) adding to said foamed first component a second component
comprising an aqueous solution of magnesium oxide at least one of
perlite and calcium carbonate, and a dispersant; and
(c) adding to said first component a third component comprising an
aqueous solution of at least one of aluminum chloride, magnesium
sulfate, magnesium chloride, zinc chloride, sulfamic acid, sulfonic
acid, citric acid, resorcinol, sodium silicate, zinc oxide, barium
metaborate, vinyl alcohol, magnesium carbonate, calium chloride and
vinyl acetate.
2. A process as claimed in claim 1, wherein said calcium carbonate
is precipitated calcium carbonate.
3. A process as claimed in claim 1, wherein said first and second
components each further comprise acrylic resin.
4. A process as claimed in claim 6, wherein said half ester of
maleic anhydride is styrene maleic anhydride.
5. A process as claimed in claim 1, wherein said first component
further comprises at least one extender selected from precipitated
calcium carbonate, feldspar, perlite, microspheres, phenolic
ballons and zeospheres.
6. A process as claimed in claim 1, wherein said alkyl sulfate is
at least one of sodium, ammonium, magnesium, diethanolamine, and
triethanolamine alkyl sulfate.
7. A process as claimed in claim 6, wherein said alkyl sulfate is
sodium or magnesium lauryl sulfate.
8. A process as claimed in claim 3, wherein said third component
comprises an aqueous solution of at least one of aluminum chloride,
magnesium sulfate, magnesium chloride, zinc chloride and sulfamic
acid.
9. A process as claimed in claim 8, wherein said third component
comprises an aqueous solution of at least one of aluminum chloride,
zinc chloride and sulfamic acid.
10. A process as claimed in claim 3, wherein the dispersant of said
second component is a sodium salt of a carboxylated
polyelectrolyte.
11. A process as claimed in claim 1, wherein said first, second and
third components are flowed and the flow rate ranges ratio of said
first, second and third components is from about 1-1.56 to about
0.25-0.56 to about 0.25-0.56, respectively.
12. A process as claimed in claim 3, wherein said first component
further comprises a 1-5% by weight aqueous solution of soap.
13. A process for producing thermally insulating foam,
comprising:
(a) mechanically foaming with air a foamable first component
comprising an aqueous solution of polyvinyl alcohol and a
dispersant; and
(b) adding to said first component a second component comprising an
aqueous solution of barium metaborate.
14. The process of claim 13, wherein the second component
additionally comprises an aqueous solution of magnesium oxide.
15. The process as claimed in claim 1, wherein the dispersant in
said first component comprises a sodium salt carboxylate
electrolyte.
16. A process as claimed in claim 1, wherein said first, second and
third components are flowed and the flow rate ranges ratio of said
first and second components is from about 1-1.56 to about
0.25-0.56, respectively.
17. A process as claimed in any of claims 1, 2 or 3, wherein said
first component is foamed through a foaming chamber, said second
component is introduced into the formed foam cells in a mixing
chamber, and any third component is thereafter introduced into the
formed foam cells.
18. A process as claimed in claim 15, further comprising
subsequently forcing the mixture of components out of said mixing
chamber and into a cavity of a structure for setting and
curing.
19. A process as claimed in claim 15, wherein said components are
each introduced through an equal number of orifices, the ratio of
the diameters of said orifices for said first, second and third
components being about 2-2.5 to about 1-1.5 to about 1-1.5,
respectively.
20. A process as claimed in claim 15, wherein said second and third
components are sprayed into said coating chamber.
21. The process of claim 3, wherein said first component is an
aqueous alkaline solution.
22. A process for producing insulating foam, comprising:
mixing magnesium oxide, alkyl sulfate, dispersant, bentonite clay
and perlite in an aqueous slurry solution;
forming a pre-foam using about 1-5% by weight alkyl sulfate and
about 3-9% by weight of at least one of magnesium sulfate and
aluminum chloride in an aqueous solution;
incorporating the pre-foam into the magnesium oxide slurry and
mixing.
23. The process of claim 22, wherein said magnesium oxide slurry
and said pre-foam are mixed and foamed in one step through the
expansion chamber of a foaming gun.
24. The process of claim 1, wherein said second component is added
before said third component.
25. The process of claim 1, wherein said third component is added
before said second component.
26. A thermal insulation foam produced by the process of claim
1.
27. A thermal insulation foam produced by the process of claim 13.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to foams which are useful for
insulating cavities and structures, such as spaces between walls in
houses. The inventive foam compositions are typically prepared in
three separate portions, namely (A) cement, (B) foam, (C) catalyst
or hardener. More particularly, in some embodiments the present
invention is directed to an insulating foam, which is produced by
mechanically mixing and foaming a first alkyl sulfate component,
adding a second magnesium oxide component to the first component,
and adding a third component which is an aqueous solution of at
least one of aluminum chloride, magnesium sulfate, magnesium
chloride, zinc chloride, sulfamic acid, sulfonic acid, citric acid,
resorcinol, sodium silicate, zinc oxide, barium metaborate, vinyl
alcohol, magnesium carbonate, calcium chloride and vinyl acetate. A
sodium salt of carboxylate polyelectrolyte, for example, that known
as Tamol 731, a Registered Trademark of Rohm and Haas, can be used
instead of the alkyl sulfate. In other embodiments, two basic
components may be used. In all embodiments air is added initially
to foam one of the components or a mixture of components. The
present application is also related to application Ser. No.
412,371, filed Aug. 27, 1983 and now abandoned.
2. Description of the Prior Art
In the past, it has been known to use an ureaformaldehyde foam for
insulating cavities and structures. However, use of this foam has
been prohibited because of alleged health hazards to occupants of
structures in which this foam has been used.
It has also been known to use a reaction of magnesium oxide with
magnesium chloride or magnesium sulfate to produce an oxychloride
or oxysulfate cement.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a foam which can be
used for insulating structures.
It is another object of this invention to provide a foam-cement
mixture wherein the foam maintains sufficient integrity to maintain
its shape and volume until the inter-mixed cement sets or hardens
to fix the composition in place.
It is a further object to provide a foam which is made from
materials which are not irritating to occupants of structures in
which the foam is used.
It is a still further object of this invention to provide a process
for making the foam discussed in the previous two objects.
It is a still further object of this invention to provide a foam
and a process for making a foam which can be easily used to install
the foam in a structure.
The above objects and others are obtained by providing a foam which
is made by combining two or three separate component mixtures. In a
first embodiment, the first component is an aqueous solution of an
alkyl sulfate, styrene maleic anhydride resin and an acrylic resin,
which is mechanically foamed. A sodium salt of a carboxylate
polyelectrolyte may be used instead of the alkyl sulfate. Maleic
anhydride resin may or may not be used with the polyelectrolyte. To
the mechanically airfoamed first component is added a second
component, which is an aqueous solution of magnesium oxide,
dispersants, acrylic resin, perlite and/or precipitated calcium
carbonate. A third component is added to these components. The
third component is an aqueous solution of aluminum chloride,
magnesium sulfate, magnesium chloride, zinc chloride, sulfamic
acid, sulfonic acid, citric acid, resorcinol, sodium silicate, zinc
oxide, barium metaborate, vinyl alcohol, magnesium carbonate,
calcium chloride or vinyl acetate.
In a second, preferred embodiment, the composition may comprise two
portions, plus air, in which the initially foamed portion comprises
an aqueous solution of polyvinyl acetate and a dispersant, and the
second, cementitious portion comprises an aqueous solution or
suspension of magnesium oxide and barium metaborate. The foam
obtained provides a good insulation "R" value and has properties
including flame resistance, low shrinkage, fast set up time, lack
of odor and nontoxicity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a system for introducing into a
remote region a four component cementitious insulating foam that
emdodies the teachings of the present invention;
FIG. 2 is a perspective view of the dispensing gun used in the
system illustrated in FIG. 1;
FIG. 3 is a perspective view with portions broken away showing a
mixing valve used in the gun of FIG. 2, and
FIG. 4 is an exploded perspective view with portions broken away
showing a spray nozzle used in the gun shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a foam and a method for producing
a foam material which has utility for insulation. The insulation
can be used either in cavities, such as those found between walls,
or in open spaces, such as attics. The foam is useful for both new
constructions and for existing structures.
The foam can be produced through the combination of three
components and air. The first component is an aqueous solution of
an alkyl sulfate, a half ester of maleic anhydride and acrylic
resin. A sodium salt of a carboxylate polyelectrolyte may be used
instead of the alkyl sulfate. Such polyelectrolytes are sold under
the Rohm and Haas trademark "Tamol 731", and described in Fordyce
et al U.S. Pat. No. 2,930,775. An alkaline aqueous solution has
been found to be particularly useful. This component is
mechanically foamed by injection of air, for example. After the
mechanical foaming a second component is added to the first
component. This second component is an aqueous solution of
magnesium oxide, dispersants, acrylic resin, perlite and/or
precipitated calcium carbonate. The acrylic polymeric resin, such
as MC76, serves as a bonding agent for the cementitious
composition. After the addition of the second component, a third
component is added. This third component is an aqueous solution of
at least one of aluminum chloride, magnesium sulfate, magnesium
chloride, zinc chloride, sulfamic acid, sulfonic acid, citric acid,
resorcinol, sodium silicate, zinc oxide, barium metaborate, vinyl
alcohol, magnesium carbonate, calcium chloride and vinyl
acetate.
In the first component, the alkyl sulfates may include sodium,
ammonium, magnesium, diethanolamine, and/or triethanolamine alkyl
sulfates. The sodium and magnesium lauryl sulfates are most
preferred. The magnesium lauryl sulfate has been found not to wet
plaster board walls upon installation. Styrene maleic anhydride is
the preferred half ester of maleic anhydride. These are sold under
the registered trademark "SMA" by ARCO Chemical, and discussed in
U.S. Pat. Nos. 3,388,106; 3,418,292; 3,178,395; 3,085,986;
3,085,994; 3,342,787; 3,392,155; 3,451,979; 3,245,933; 3,046,246;
and 3,245,933. Preferably, the acrylic resin is in the form of a
dried powder. The foamed first component provides a support for the
cement formed by the second and third components. Thus, any
foamable material could be used for the first component, as long as
the foam exhibits enough strength and does not collapse before the
cementitious portion of the composition obtains sufficient rigidity
and integrity to maintain the solid shape of the foam.
For the dispersants of the second component, a sodium salt of a
carboxylate polyelectrolyte may advantageously be used. In addition
to the "Tamol" dispersants, a dispersant known as "Daxad 30", a
Registered Trademark of W. R. Grace & Co., is useful. It is
desirable that precipitated calcium carbonate be used in the second
component because of its property of fluffiness. However, other
forms of calcium carbonate could be used.
Among the ingredients listed for the third component, the most
perferred solutions include aluminum chloride, magnesium sulfate,
magnesium chloride, zinc chloride or sulfamic acid. One example of
a third component would be an aqueous solution including 25 parts
of water, 3-6 parts of aluminum chloride and 6-3 parts of magnesium
sulfate. It is preferred that the magnesium sulfate be of the
synthetic type which has about 17% magnesium present. This
magnesium sulfate has been found to contribute to better foam
stabilization than Epsom salts. It has also been discovered that
zinc oxide and barium metaborate can provide increased hardness and
decreased setting time for the foam.
The material formed by this process can be injected into a
structure and will hold its form. The foam sets in from 1-10
minutes and has a cure time of approximately 7 days at ambient
temperatures. The working time or pot life of the combined first
and second components prior to addition of the third component can
vary from 1-5 hours. This can be controlled through the use of the
polyelectrolyte dispersants. The density of the finished foam is
controlled by adjusting the air entrainment in the finished foam. A
small variable amount of water remains in the foam, depending upon
the relative humidity of the atmosphere in which it is
installed.
A basic reaction is believed to involve magnesium oxide and
aluminum chloride, magnesium sulfate, magnesium chloride, zinc
chloride, sulfamic acid, sodium silicate, zinc oxide, barium
metaborate, vinyl alcohol, magnesium carbonate, calcium chloride
and/or vinyl acetate. The magnesium oxide is preferably dispersed
with dispersants, acrylic resin, perlite and/or precipitated
carbonate to form the second component, and an aqueous solution of
an alkyl sulfate with a half ester of a maleic anhydride to form
the first component, which has been foamed. This combination is
then reacted with the aqueous third component which may comprise
aluminum chloride, magnesium sulfate, magnesium chloride, zinc
chloride, sulfamic acid, sodium silicate, zinc oxide, barium
metaborate, vinyl alcohol, magnesium carbonate, calcium chloride
and/or vinyl acetate in aqueous solution. It is believed that the
alkyl sulfates control the formation and density of foam cell
structure. These are reinforced with the acrylic resin and half
ester of maleic anhydride. The basic activity is controlled by the
size of magnesium oxide particles and by the dispersants.
Extenders may also be included in the first component. The
extenders may be selected from precipitated calcium carbonate,
feldspar, perlite, microspheres phenolic ballons and zeospheres.
Microspheres are micron-sized hollow spheres of sodium
silicate.
It is preferred that the final foam composition include 5-75% by
weight magnesium oxide. It has been discovered that a 1-5% by
weight solution of soap in water can be included with the first
component to decrease the water absorption of the final foam. A
foam without the soap solution had a water absorption of 15-40% by
weight. After the addition of this soap solution, the foam obtained
showed a water absorption which was reduced to 1-2% by weight.
Ivory brand and Fels Naptha brand soaps have found to be
useful.
Successful foams were produced using the following compositions.
Percentages are in percent by weight of total material.
EXAMPLE I
First Component
9% Tamol 731
3% Acrylic resin
15% Precipitated calcium carbonate
10% Water
Second Component
40% Magnesium oxide
15% Water
Third Component
3% Aluminum chloride
3% Magnesium chloride
2% Water
Of course, air, to form the bubbled or cellular foam, is an
additional component.
EXAMPLE II
The "Tamol 731" of Example I was replaced by 9% of styrene-maleic
anhydride resin.
EXAMPLE III
The "Tamol 731" of Example I was replaced by 2.5% sodium lauryl
sulfate and 6.5% water.
Still other Examples show the inventive compositions in actual
weights, and in total weight percentages:
EXAMPLE IV
______________________________________ First Component (B) 0.25%
Tamol 731 0.25 lb. 0.25% Epsom salts 0.25 lb. 0.25% Poly-vinyl
acetate 0.25 lb. 29% Water 30.0 lb. Second Component (A) 12%
Magnesium oxide 12.5 lb. 24% Water 25.0 lb. 0.25% Daxad 30 0.25 lb.
1.0% MC 76 acrylic 1.0 lb. 0.25% SMA styrene maleic 0.25 lb.
anhydride 1.0% Polyvinyl alcohol 1.0 lb. 0.5% Tamol 165 0.5 lb.
Third Component (C) 6.7% Aluminum chloride 7.0 lb. 5.8% Epsom salts
6.0 lb. 19.2% Water 20.0 lb.
______________________________________
Of course, air, to form the bubbled or cellular foam, is an
additional component.
EXAMPLE V
In another example, the composition of Example IV uses a modified
Third Component (C):
______________________________________ First Component (B) 0.25%
Tamol 731 0.25 lb. 0.25% Epsom salts 0.25 lb. 0.25% Poly-vinyl
acetate 0.25 lb. 29% Water 30.0 lb. Second Component (A) 12.3%
Magnesium oxide 12.5 lb. 25.5% Water 25.0 lb. 0.25% Daxad 30 0.25
lb. 1.0% MC 76 acrylic 1.0 lb. 0.25% SMA styrene maleic 0.25 lb.
anhydride 1.0% Polyvinyl alcohol 1.0 lb. 0.5% Tamol 165 0.5 lb.
Third Component (C) 3.0% Aluminum chloride 3.0 lb. 4.0% Polyvinyl
alcohol 4.0 lb. 19.5% Water 20.0 lb.
______________________________________
Additionally, certain compositions which are even simpler, and can
be formed from only two separate portions, are now known to perform
quite satisfactorily, as indicated in Example VI below:
EXAMPLE VI
______________________________________ First Component (B)
Polyvinyl acetate (8%) about 15.5-21.2% or about 6-25 lb. Tamol,
spray dried about 0.3-1.7% or about 0.12-2.0 lb. Water about
38.8-33.9% or about 15-40 lb. Second Component (A) Magnesium oxide
about 7.7-15.3% or about 3-18 lb. Busan about 0.6-1.7% or about
0.2-2.0 lb. Water about 36.2-25.4% or about 14-30 lb. Daxad 30
about 0.6-0.9% or about 0.25-1 lb.
______________________________________
Air, to form the bubbled or cellular foam, initially with the first
Component (B), is an additional component. In this preferred
composition it is believed that the mixture of polyvinyl alcohol
from the first Component (B) and the Busan from the second
Component (A) quickly react to cause setting of the foam matrix to
provide quickly a foam of excellent integrity to support cement
until it hardens in place thus contributing its own even more
permanent integrity to the insulative foam product. Busan.TM. is a
barium metaborate composition available from Buckman Laboratories.
Either 4 mol or 8 mol metaborate may be used. In this preferred
composition it is believed that the mixture of polyvinyl alcohol
from first component (B), and the Busan from second component (A)
quickly react to form a cellular foam, with or without the presence
of magnesium oxide. When present, magnesium oxide, contributes long
term integrity and fire resistance to the foam.
EXAMPLE VII
In still another method of preparing a cellular foam, the known
quick reaction between calcium chloride and sodium silicate is
utilized in a new application. The following formula provides an
insulating foam structure:
______________________________________ First Component Calcium
Chloride about 3.5-8.4% or about 1-5 lb. Water about 53.4-33.6 or
about 15-20 lb. Second Component Sodium Silicate about 7.1-13.5% or
about 2-13.5 lb. Water about 35.5-42.1% or about 10-25 lb. Fluorad
FC100 about 0.3-2.6% or about 0.1-1.5 lb.
______________________________________
Fluorad is a Registered Trademark of Minnesota Mining and
Manufacturing Co., and is a fluorinated alkyl amphoteric mixture
surfactant. Daxad 21, a Registered Trademark of W. R. Grace &
Co. may also be used. Daxad 21 is a mono-calcium salt of
polymerized aryl alkyl sulfonic acids.
The foam formation technique described in Example VI may also be
used with this Example VII composition.
Further, addition of mica (muscovite) to the First Component
contributes to the reaction of the calcium chloride with the sodium
silicate and improves the water resistance of the resultant foam.
Addition of polyvinyl alcohol to the First Component contributes to
the expandability and integrity of the foam.
Weight ratios of sodium silicate (SiO.sub.2 /NaO.sub.2) in the
range of about 3.2 to 42.2.degree.Be has been found
satisfactory.
Although the exact reaction mechanism of the inventive two portion
foam insulation system is not yet fully understood, it is believed
that the chemistry which occurs during laminar flow mixing
contributes to the desirable results of the present invention. As
previously indicated, the idea of having a foam system with
sufficient integrity to support cement until the cement can cure is
carried out in the composition of Example VI by the very fast
reaction between the polyvinyl alcohol in the First Component (B)
which is foamed, and the Busan, barium metaborate, in the cement
containing Second Component (A). In the other exemplary
compositions the third portion contains aluminum chloride and Epsom
salts, both of which are hardeners for cement, and which contribute
to fast hardening of the cement portion of the composition.
However, the aluminum chloride also may quickly, but partially,
react with the Tamol to form an initial gel. Tamol 165 is an
ammonium salt of polymeric carboxylic acid, and Tamol 731 SD is a
sodium salt carboxylate polyelectrolyte, both available from Rohm
& Haas Co.
Additionally, there is a possible chemical reaction between the
Tamol and Epsom salts to form a magnesium salt which exhibits
better properties for foaming than Tamol alone. Polyvinyl acetate,
spray dried, as an additive, is possibly catalytic to this reaction
which further improves the properties of the foams.
With reference to the drawings and, in particular, to FIG. 1, there
is shown a foaming gun system 10 for manufacturing and dispensing a
four component insulating foam. One of the components used to
generate the foam is compressed air provided by a conventional air
compressor 11. The air is combined wth a foaming agent (first
component) in a foaming or expansion chamber 12. The foaming agent
is stored in container 13 and delivered by line 14 to a mixing
valve 15 located at the entrance to the foaming chamber. As will be
explained in greater detail below, compressed air is also delivered
to the valve 15 via line 17 wherein the two materials are brought
together in metered amounts to create a latherlike substance
containing a multitude of air bubbles. To assist in the generation
of the bubbles, the foaming or expansion chamber 12 is packed with
a finely divided material 19, such as fine steel wool or glass
beads, which creates sufficient turbulence in the flow stream to
ensure that the material is well aerated.
The foaming chamber 12 is connected directly in series with a
second coating or mixing chamber 20 whereupon the flow of foam that
is generated in the foaming chamber is caused to flow directly into
and through the second chamber. Although not shown, a foam
penetratable seal is located at the entrance to the coating or
mixing chamber 20 which prevents the packing material 19 from
passing between chambers.
A pair of inlet ports 22 and 23 are mounted in the side wall of the
coating or mixing chamber 20 to permit further materials to be
added to the foam flow. One of these two coating materials is a
cementitious substance (second component) used for preparing a fast
setting insulation. The cementitious material is stored in the form
of an aqueous solution in container 25 and is brought to inlet port
23 via supply line 26. A fast setting material of this type that is
suitable for use in the present system is magnesium oxide. The
second coating material (third component), which is stored in
container 28, is an agent that is capable of reacting with the
cementitious material to produce rapid hardening of the foam. The
material, upon hardening, also exhibits early strength so that it
will become self-supporting almost immediately upon being injected
into a cavity. A hose 30 is connected to the outlet of the coating
or mixing chamber 20 through which the foam is dispensed into a
wall cavity 31 or any other suitable region that is to be
insulated. The hose and the coating or mixing chamber 20 combine to
provide a relatively long flow path wherein the coating ingredients
combine or mix with the foam under laminar flow conditions to
create a well defined homogeneous mixture.
In the embodiment of the invention shown in FIG. 1, the reacting
agent is the first material introduced into the mixing chamber at
inlet port 22. The cementitious material is then introduced into
the chamber at the second inlet port 23. It is important for the
proper manufacture of the present insulation to space the two inlet
ports far enough apart to allow sufficient time for the first
introduced material to become uniformly distributed in the foam
before the second material is added. Although the exact mechanism
by which the two coating materials combine is not fully understood,
it is known that if they are added simultaneously or too close
together, the material will not react in a predictable manner to
produce optimum foam. The order in which the two coating materials
are added to the mix is immaterial, but it is perferable to add the
magnesium oxide (second) component to the foam before the third
component. What is important, however, is it is believed that the
first introduced material must have sufficient time to
substantially coat all of the bubbles in the foam before the second
is added. As a result, the cementitious material, upon reacting
with the agent, is able to create a hard shell about each bubble to
trap or encapsulate the air within the foam blanket. It is believed
that by bringing the two coating materials into the system at about
the same time causes the bubbles to collapse before encapsulation
leading to a failure in the manufacturing process.
The foaming agent and the two coating materials are each drawn from
their respective containers by means of independent pumps 34-36
that are operatively connected into appropriate delivery lines. The
materials are pumped at relatively high pressure to the gun section
40 of the system which is illustrated in greater detail in FIG. 2.
The high pressure flow in each line, as well as the high pressure
flow of air carried by line 17, is stepped down before entering the
gun by means of small pressure regulators 41-44. The regulators are
individually set so that the pressure of the fluid traveling in
each line is brought to an optimum value before the fluid is
delivered to the gun. The gun is furnished with a trigger
mechanism, generally referenced 47, that enables the operator to
quickly actuate or shut down the gun. The trigger includes four
on-off valves 49--49 of similar design which are positioned in each
supply line downstream from the pressure regulators. Each on-off
valve is connected to the trigger 50 through a quick acting lever
mechanism 51.
The foaming agent moving through line 14 is passed into the central
opening 53 contained in the previously noted mixing valve 15 (FIG.
3). The opening terminates at a metering orifice 54 whereby a
metered amount of the foaming agent enters the foaming chamber. Air
from line 17 is also brought into the mixing valve directly behind
a control ring 55. The ring, in turn, has a series of equally
spaced nozzle passages 56--56 formed therein which both turn and
shape the air stream entering the foaming chamber. The passages are
contoured to impart a volute-like motion to the air stream which
enhances bubble generation and provides for thorough mixing at the
entrance to the chamber. Bubble generation is further enhanced as
the mixture moves through the packing material.
As previously noted, the two coating materials are brought into the
flow further downstream in the coating or mixing chamber 20. Inlet
port 22 is housed within a Y-connector 57 while inlet port 23 is
similarly housed within T-connector 58. To insure that each of the
two materials thoroughly coat the bubbles, they are sprayed into
the foam in the form of a fine mist. A spray nozzle 60, as
illustrated in FIG. 4, is used for this purpose. The nozzle is
contained in the neck section of the connector and is positioned to
direct the mist into the foam without disturbing the laminar nature
of the flow. Each spray nozzle 60 includes a body section 62 that
is slidably received in the associated connector. The end wall 63
of the body section contains a fine hole 64 that is designed to
bring the material passing therethrough into a well defined spray
pattern. The inside of the body section is bored out and th bored
passage 65 threaded to receive a threaded collar 68 radially
disposed on control head 67. The head has a series of entrance
slots 69--69 formed therein which meter material inot the nozzle.
After entering the nozzle, the material is caused to pass through a
series of contoured vanes 70--70 that whirls the material as it
passes through the hole 64. This, in turn, imparts a circular
motion to the mist entering the chamber providing for a more
uniform and homogeneous coating of the bubbles in the flow stream.
The foam material then enters hose 30 and is ultimately dispensed
into the insulating region. The materials continue to mix or blend
under laminar conditions in the hose, which actually is an
extension of the coating chamber. The hose therefore should be
between six and ten feet long to enable the blending process to
proceed to near completion. Shut off valves 72 and 73 are provided
at the inlet ports which are used by the operator to check the
condition of the supply line and the performance of the gun.
An air bypass circuit, generally referenced 75, is mounted upon the
gun which allows the operator to reroute air only into the gun for
the purpose of cleaning the two chambers and the hose. The bypass
loop includes a line 76 and a manually operated bypass valve 77
which takes air from the air line 17 and brings it around the
trigger directly into the foaming chamber. A second shutoff valve
80 is positioned in the air line 17 directly at the entrance to the
mixing valve which isolates the bypass system from the trigger
mechanism. To clean the gun, the shutoff valve 80 is closed and the
bypass valve 77 is opened permitting compressed air to bypass the
trigger mechanism and thus purge the gun without having to
disconnect the material pumps.
Using this foam gun, the first component is foamed through a mixing
chamber with air to produce a foam having the consistency of
shaving cream. Next, one of the coating materials is introduced
into the thus-formed foam cells as the foam is passed to the
coating chamber. After this, the other coating material is
introduced into the formed-foam structure and the combined
ingredients are forced out of the mixing chamber with air pressure
through the hose and into an existing cavity for setting and
curing.
It is preferred that each component is introduced to the gun
through an equal number of orifices. The ratio of the ranges of the
orifice sizes for the first, second and third components is about
2-2.5 to about 1-1.5 to about 1-1.5, respectively. Since the flow
rate is proportional to the cross-sectional area of the orifices
(assuming equal pressure), this results in a ratio of flow rate
ranges of about 1-1.56 to about 0.25-0.56 to about 0.25-0.56,
respectively.
The acrylic resin in the first and second components is believed to
enhance foamability. The perlite and/or calcium carbonate of the
first component is used for extending the foam. Thus, although
these elements are desirable, they are not believed to be essential
in obtaining a useable foam.
A second method for preparing the foam of the present invention may
be performed in which a conventional foam gun may be used.
Magnesium oxide is mixed with alkyl sulfates, dispersants,
bentonite clay and perlite in an aqueous slurry-solution. A
pre-foam is formed in an appropriate mixer using from 1-5% of alkyl
sulfate and 3-9% of aluminum chloride and/or magnesium sulfate in
an aqueous solution. The other ingredients described for the third
component in the method described above could also be used. From
2-80% of the pre-foamed alkyl sulfate is incorporated and mixed
with the magnesium oxide slurry for about 1 minute. The resulting
foamed cell structure will set and cure into useable insulation
foam. The density of the cell formation is controlled by the amount
of alkyl sulfate mixture incorporated into the magnesium oxide
slurry. These two components may also be mixed and foamed in a one
step operation using the expansion chamber of a foaming gun. The
cell structure obtained by this process does not appear to exhibit
maximum cell formation and density, while the existing equipment
cell formation is suppressed.
* * * * *